Unconjugated serum oestriol levels in mother and baby with meconium staining of the amniotic fluid.

To examine the effect on oestrogen metabolism of the stimulus which causes the passage of meconium, we measured maternal venous and cord artery and vein serum unconjugated oestriol levels in 46 patients with meconium staining of the amniotic fluid and 19 controls. Mean cord vein oestriol levels were significantly lower than in controls in the presence of meconium stained amniotic fluid and no fetal acidosis (cord artery buffer base of 36.2 meq/l or more) (P less than 0.02). The same tendency was seen with acidotic infants (P less than 0.05). There is thus evidence of a change in oestrogen metabolism associated with meconium staining of the amniotic fluid.